This invention relates to a retainer ring which is a component of a freewheel clutch and which has generally two substantially radially extending annular discs connected to one another by means of circumferentially adjacent, axially parallel links for accommodating clamping elements (sprags) having flat end faces. The sprags are held captive in the retainer ring by virtue of the particular shape of the links.
One-part or multipart retainer rings of the above-outlined type are known in various configurations such as disclosed, for example, in U.S. Pat. Nos. 3,443,672 and 3,702,649 or German Pat. No. 1,915,567. In these arrangements preponderantly sprags of flat end faces are used. This represents significant manufacturing economy because the sprags may be directly severed from a drawn steel wire of predetermined cross-sectional configuration and there is no need to provide laterally extending bearing stubs which involves expensive manufacturing steps.
On the other hand, it is a disadvantage of the known retainer rings that for each ring dimension a separate die casting tool is needed which represents a very significant expense.
Retainer rings for freewheel clutches are known which include pivotally interconnected ring components arranged in a circumferential sequence and usable for any clutch diameter. Such arrangements are disclosed in U.S. Pat. No. 3,702,649 (FIGS. 9 through 14) and U.S. Pat. No. 3,543,894. It is a disadvantage of these structures, however, that the individual retainer ring components, because of their snap-in connection, are not sufficiently stable as regards circumferentially generated forces. In case of impact-like torque surges, for example, at moments of clutch engagement from a freewheeling state, because of the non-uniform arrangement of the individual sprags, significant circumferential forces are generated whereby the retainer ring components may become disengaged from their snapped-in state. As a result, the sprags will be no longer guided in the circumferential direction, and they may thus slide off their pressing spring and become inoperative. While this disadvantage may be eliminated by sprags which have laterally extending support pins held in the annular discs of the retainer ring, such an arrangement involves substantial expenses as discussed above.